Radio direction finder



1937 4 'Sheets-Sheet 1 Aug. l, 1939.' s. R. WAGNER RADIO DIRECTION VFINDER Filed June 15,

INVENTOR STEPHAN R. MMG/VER ATTORN EY Aug. 1, 1939. s. R. WAGNER l RADIO DIRECTION FINDER Filed June l5, 1937 `4 Sheets-Sheet' 2` .ATTORNEY ug. l, 1939. s R. WAGNER I 2,167,787

RADIO DIRECTION FINDER Filed June l5, 1937 4 Sheets-Sheet 3 ze BY 32 ATTORNEY Aug.1,1939. sRWAGNR '2,167,787

RADIO vDIRECTION FINDER STEPHAN R MGT/Vfl? ATTORN EY Q: l B

Patented Aug. l, 1939 ori-*ic RADIO DIRECTION FINDER stephan a. Wagner, Elizabeth, N. i., assignmto Federal Telegraph Company, Newark, N. J., a corporation of California Application June 15, 1937, Serial No. 148,278

12 Claims. (CL. Z50-11) The present invention relates to radio compasses or direction iinders especially for use on ships, and more particularly to the typeoi compass in which a loop or directional antenna is rotated under manual control into alignment with the direction of a received radio signal, and in which after such an alignment of the antenna an indicating device is adapted to show the bearing of the radio signal either with respect to thej ship or with respect to the cardinal geographic directions such as true north or magnetic north, etc. The first mentioned bearing may be known as the off-bow bearing and the second mentioned as the absolute bearing. Y

It is an object of the present invention to provide a simple self-contained unitary structure which shall enable bearings of either the oH-bow type or absolute type to be taken accurately and conveniently. It is a further object to provide such a compass in which the manual control for rotating the loop antenna is in the form of a handwheel and in which the essential visual indicating equipment for taking bearings of either type is located in the center of such handwheel and disposed in such a manner that the relationship of the cardinal geographic directions, the direction of the keel of the ship, and the direction of the received radio beam can be readily observed and easily visualized by an observer who is operating the handwheel with both hands.

It is a particular object f the. present invention to arrange the visual indicating means in the form of two dials and one pointer concentrically rotatable with regard not only to one another but also with regard to the handwheel which surrounds them and to provide driving means for these four concentric mechanisms, that is the handwheel, outer dial, inner dial and pointer, which shall be disposed wholly behind these mechanisms so that the front side of the controlling and indicating panel of the compass shall be free from'shafts, gears, or other supporting or driving mechanisms, and so that the indicating devices may be wholly visible at all times.

It is a further object to provide a rugged and reliable mechanism as above described in which the mechanicalerrors due to lost motion, friction or springing of the parts shall be reduced to a minimum. It is a further specic object ofthe present invention to provide a mechanism for supporting and driving these concentric indicating devices inside of and concentric with a controll1 ng handwheel in such manner that the whole arrangement may be readily manufactured and maintained. For this purpose the four coaxially rotatable control and indicating devices are constructed in one separable unit in which are included all the necessary gears for driving the various indicating devices from the handwheel or froml other control means, and the engagement between this unit and the other portionsA ofthe radio compass such as the shaftwhlch rotates the loop antenna is so arranged that the unit may be readily removed from the compass or replaced therein.

According to another feature' of the present invention a quadrature compensating mechanism which comprises a light sheet metal cam and a link motion made of comparatively light parts and which is to be located immediately adjacent the pointer of the indicating mechanism so as to avoid injury to such compensating mechanism,

is for this purpose mounted inside of a stationary bowl or basket which carries the inner dial. This stationary bowl or basket is in turn enclosed by a second basket which carries the second dial, which again is enclosed by a third basket or spider framework supporting the handwheel. According invention; Fig. 2 is a sectional elevation of the upper part of the compass including the loop antenna; Fig. 3 is a Somewhat schematic sectional elevation of the control and indicating unit generally shown as I5 in Fig. 1; Fig. 4 is a somewhat schematic-perspective of the compensating mechanism shown in Fig. 3; and Fig.' 5 is a more 40 Y detailed sectional elevation showing the preferred construction of the. unit schematically reprsented in Figs.I 3 and 4.

In these drawings, and especially in Figs. 3 and 4, many of the sub-assemblies of members have been schematically represented as if they were formed of one single piece, even though in some instances the assembly of the device would be impossible or impracticable if the sub-assemblies were actually constructed of one pieces as shown. This schematic showing has been employed in order to facilitate the comprehension of the structure and operation of the present invention and it will be understood that in the actual construction of the invention many of vseparate members rigidly nxed together by suitable means, and that each of these composite members may comprise several different materials.

Referring more specifically to Figs. land 2 an aluminum cabinet I of which the lower portion is made of sheet aluminum and the .upper portion is a casting, supports an aluminum receiver panel 2 which has an inclined face. On this panel 2 is mounted a receiving set 3 which is adapted to be energized by signals from a loop antenna 9 and to deliver an audible indication of the correct alignment of this loop by means of loud speaker 4, -which is mounted in the top of cabinet I or alternatively by means of earphones (not shown), which may be plugged into a jack in the receiver panel-2. A storm door l covers the receiver panel when the instrument is not in use. l The loop antenna 9 is adapted to be rotated by means of coupling ring 1 from the shaft 9,' which is in turn coupled by another flexible coupling ring 1' to the upper portion of rotary gear member 9. Electrical connection with the antenna is obtained over the three wires Il which are I brought down outside of shaft 9 so as to mini- Amize distributed capacity and which thenv pass `for a short distance inside of member 9 and are joined to terminal studs II.

studs are connected to sliprings I2, and in fact l are shown integral therewith.' Brushes I3 rest against these slips rings I2 to collect the signal from the antenna and these brushes I3 are con-y nected by leads I4 to the input ofreceiver' 3.

The output of receiver 3 is connected by other leads (not shown) to loud speaker 4 and tov a jack adapted to receive signals, (not shown). The upper front face of cabinet I is sloped to form a control and indicating panel and in this panel is set the control and indicating unit I9 which engages with and drives the rotary gear member 9 as explained hereafter. A clampingor braking member I9' is provided which bears upon a portion of rotary gear member 9 in order to lock the loop in any position to which it has been set or to introduce the desired resistance to rotation so that the loop may be more readily controlled in windy weather. 1

'I'he construction and operation of control and indicating unit I9 may be more clearly seen from l Fig. 3 which represents this'unit in section. As

' shown in Fig. 3 the stationary frame I1 of the control and indicating unit is shaped so as to define a substantially annular cavity open to the front face of the unit. This frame I1 .may be considered as comprising essentially a drum shaped chamber I9 openat the front face andl provided with a flange for mounting it in the cabinet I, the rear face of this drum shaped chamber being formed with a reentrant hollow central boss I9, 29, which extends forward from the rear face of the drum shaped chamber almost up to the plane of the open front face of this.

chamber. 'I'he hollow central bossA I9, 2l is sharply reduced in diameter so es to form. a narrow neck 2I which divides the boss into an open rear portion 29 of cylindrical shape and a closed 'I'hese terminal rear portion 23 of the central boss. Hand wheel assembly 22 comprises a ring gear portion 23 which is located directly in line with the bearing surface upon which the hand wheel is supported so as to insure an accurate and very rigid positioning of this gear. Spur gear 24 which meshes with this ring gear 23 is mounted o'n-a Jack-shaft 29 which is journaled in an extension 29 of frame I1. Preferably the extension 29 of frame I1 and the rear portion 29 of the central boss of this frame are cast in one unitary piece so that gear 24 will be rigidly and accurately located with respect to gear 23. On the same jack-shaft 29 is fixed a bevel gear 21 which meshes with antenna gear member 9, when thevunit is in position in the cabinet I. Also fixed to this jackshaft 29 is another spur gear 23 fordriving the indicator mechanism when the handwheei is rotated.

Inside of the central boss I9, 29 is the main indicator shaft 29 which extends from inside the compensator housing through the narrow neck portion 2I and the lower portion 29 to the rear side of main frame I1. This main indicator shaft 29 is journaled in the stationary frame member I1 as shown and carries a spur gear 33 which meshes with spur gear 23 so as to cause the rotation of shaft 29 when the hand wheel 22 is rotated.. Preferably the pitch diameter of gear 33 is the same as the pitch diameter of ring gear 23, and the pitch diameters of spur gears 24 and 23 are equal, so that the main indicator shaft 29 will rotate in synchronism with hand wheel 22. If desired, however, these gear ratios may be l modified to -introduce a reduction between the rotation of handwheel assembly 22 and the rotation of main indicator shaft 29. Pointer cap 3i is rotatably mounted on the front end of the main indicator shaft 29 and extends through the front face of compensator housing I9. vCap 3l is driven from the main compensator arm 32, which is fixed `to shaft 29, by means of the compensatorv linkage more clearly shown in Fig. 3.

As described more fully hereafter, this compensator linkage drives cap 3| essentially in unison with shaft 29 except for a lagging or leading rotary displacement of a portion of a quadrant which may be-introduced by the non-circularity of cam 39. Cap 3i, therefore, rotates with shaft 29 and is essentially xed with respect thereto,

except for a rotary displacement of plus or minus a part-of the quadrant. A pointer 33 is attached by screw 34 to the cap 3l so as to rotate over the face of front wail 39 of the compensator housing I9. y'I'his front wall 39 which supports cam 35 is preferably removable from the rest of housing I9-and on its front face is suitably engraved to serve as a dial. This member 36 is hereafter called the off-bow dial. Concentrically located just outside of this off-bowdial 36 'there is dis- Aposed the absolute dial 31 whose front face is suitably engraved to designate the cardinal geographic directions, i. e. the bearings with respect to true north.- 4

- This dial 31 iscarried by a basket member 33 which is journaled on an outer cylindrical surface of neck 2i of the central boss I9, 29. Basket member 33 comprises a ring gear portion 39 disposed directly opposite the bearing surface which supports this basket member,v so as to` insure accuracy and rigidity of' positioning of the gear. Gear 39 meshes with another gear 49 which is driven from a special drive mechanism 4I. This special drive mechanism 4I is of the type commercially marketed under the name Sperry comanew/sv well known, need not be further described.. It

may be noted, however, that evenif drive 4| is disassociated from the master compass for the purpose of adjusting dial 31 manually, and is then reassociated with the master compass, this drive 4| will immediately rotate gear 40 so as to bring gear 39 and dial 31 into correspondence with the master compass even if the master compass or the drive mechanism 4| or both have been altered in position between the time of their the loop antenna at all times.

disassociation and the time of their reconnection. Gear 4|| is also adapted to be rotated manually bymeans of a crown gear (not shown) which meshes with another gear 42 fixed to gear 40. Normally this crown gear is disengaged from gear 42 but may be engaged manually after disassociating drive mechanism 4| from the master compass. Dial 31 is therefore normally rotated under the control of the master compass by means of drive mechanism 4| but may alternatively be controlled manually.

It will thus be seen that the indicating and control unit provides a rotatable pointer 33v adapted to be read in connection with either the central off-bow dial 36 or the outer absolute dial 31, both of these dials, as well as the pointer being located centrally inside of the control hand wheel 22. The o-bow dial 3B is fixed and the outer dial 31 is adjustable in conformity with the manual or automatic adjusting means above described. Thus, when pointer 33 indicates against dial 36 a given bearing with respect to the keel of the ship, this pointer 33 will simultaneously indicate against dial 31 the corresponding direction with respect to the absolute north and south.

As previously mentioned, gear 21 meshes with antenna gear member 9 when the control and indicating unit is in position in the cabinet. The gear ratio between the gear portion lof member 9 and the bevel gear 21 on jack shaft 25 is exactly the Asame as the gear ratio between the gears 30 and 23.' 'I'his gear member 9 directly drives theloop antenna by means of exible couplingring 1 and drive shaft 6, therefore, .the rotation of shaft 29 exactly corresponds to the rotation of In the preferred form of my invention the rotation of hand wheel 22 also corresponds to the rotation of shaft 29 and to the rotation of the loop antenna; but even if a reduction is introduced between hand wheel member 22 and indicating shaft 29, the gear ratio between gear member 9 and shaft 29 must not be altered but must always be equal to unity.

It is clear from the above that if the direction of the loop could be considered as accurately representing the direction of the incoming radio signal, the pointer 33 could be directly and rigidly connected to indicating shaft 29. It' is known however, that the direction of reception of a signal with respect to the bow of the ship will not exactly correspond to the setting of the loop antenna with respect to the bow of the ship because of the` influence of metal portions of the y ship upon the incoming signal. The deviation is constant for any given relationship of the loop antenna to the ship and can be predetermined.

rection of shaft 29 and since the'deviation of the signal with respect to the loop antenna is exactly compensated by the displacement of cap 3| with respect `to shaft 29, cap 3| which carries the pointer will at all times when the loop is adjusted for minimum reception, bear the same relationship to dial 36 as the direction of the incoming signal bears to the keel line of the ship.

From the above analysis it is evident thatl oibow bearings can be directly taken by reading the position of the pointer against dial 36. Ab-

vsolute bearings are equally directly indicated.

As previously explained dial 31 is maintained by means of the automatic or manual adjustment in such a position that the bow position or zero point in the scale of dial 33 will bear the same relation with respect to the North graduation on dial 31 as the bow of the ship actually bears with respect to the true north direction. Therefore, the relationship of pointer 33 to dial 31 will indicate directly the direction of the signal with respect to the true north when the loop is set for minimum reception. Thus, as soon as the loop has been adjusted by means of the hand wheel to give the least signal, both the off-bow and absolute bearings of the signals are directly indicated by the position of the pointer with respect of the signals with respect to the ship Iand to the true north readily observable, but also the relationship of the three factors may be readily visualized and understood since the outer card may be considered as representing a map of the sea upon which the ship is sailing; the inner dial may be considered as representing the ship itself and the pointer may be considered as representing the true direction of the signals. It has been briefly mentioned that the cutting of cam 35 serves to displace-pointer cap 3| with respect to indicating shaft 29 so as to compensate for the deviation of the loop direction with respect to the two directions of the signal. The link motion by which this displacement of cap 3| is effected under the controlof cam 35; is clearly shown in Fig. 4. Bell crank arm 44 is `piv'oted on pin 45 and thus is carried around in unison with indieating shaft 29 since the pin 45 is rigidly fixed. in arm 32 which' is integral with or-fixedwith4 respect to the indicating shaft 29. Pointer cap 3| is connected to bell crank 44 by means of link 43 and thus this cap also rotates with shaft 29 so long as crank arm 44 does not rock around graduated so that this cam may readily be cut.

to effect the necessary lagging or leadingcorrections. It is thus necessary only, to observe and record the errors lor deviations of the signal with respect to the loop at'small intervals of rotation the pivot pin 45. The rocking of crank 44 around l of the loop. Then from this data cam 3'5 can be immediately cut by the aid of the graduations on its face, so as to completely correct for these deviations.

The preferred practical embodiment of the arrangement schematically represented in Fig. 3, is

shown in greater detail in Fig. 5. As shown in this figure, the frame structure designated generally by reference numeral l1, comprises a substantially drum-shaped aluminum casting I8 having a central reentrantboss 29 to which a bearing ring 49 is attached by screws 50 and a substantially basket-shaped brass casting I9 having va central quill portion 5I. 'I'his quill nts tightly in a corresponding central hole in boss portion 20 of casting I8 and issecured by a split clamping nut 52 which is threaded upon the quill and which is locked by screw 53. A key pin 54I serves to register basket I9 in the correct angular relation with respect to frame I8 and to prevent relative rotation of these two parts. For lubrication there are provided a grease cup 49 which supplies lubrication to the outside cylindrical surface of boss 20 as weil as to a cylindrical bearing surface inside of quill 5|, and another grease cup 49 which lubricates a cylindrical bearing surface that is formed inside of extension 26 of casting I8. The dial and cam assembly |00, which may also be considered as part of the frame structure, comprises a dial plate 36 having on its front face a representation of the structure in which the direction finder is to be used, for example a ship or other vessel, and suitable graduations to facilitate the reading of off dial bearings as described in connection with the previous gures. This dial plate 38 is screwed to lugs 55 of basket member I9. Supported from I dial plate 3B is cam plate 35 which is spaced from the dial plate by spacer 53 and held in position between this spacer and clamping ring 51 by screws 58 which extend throughthe dial plate, spacing member and-cam plate, and are threaded into the clamping ring. All the above mentioned portions of the control and indicating unit are fixed withrespect to one another during operation, and are collectively referred to as the frame structure, being designated generally by the reference numeral I1.

Handwheel assembly 22 comprises a ring gear l.'59 journaled on the outer cylindrical surface of boss 2,0 and retained by bearing ring 49.' To this ring gear '59 is screwed the handwheel casting 65. Handwheel casting 35 comprises an in ner ring portion 3| which is attached to ring gear 59 by screws 66, a basket-formed set of spokes 60, and intermediate ring portion 62, a set of three handwheel spokes 94, and a handwheel portion 63. The intermediate ring portion 92 of this handwheel casting 35 is formed withv a depending fiange and a groove which cooperate with ailange on the upper edge of casting I9 of the frame structure, thus forming a seal' of the labyrinth type for excluding moisture and dirt. The intermediate ring portion 32 of the handwheel casting 35 does not, however, touch the casting I 3 of the frame structure, but this handwheel casting 35 is wholly supported by the ring gear 59. A glass dial cover 31 is carried by intermediate ring portion 92 of the handwheel casting, being retained in position by snap ring 6B.

Inside of handwheel casting 35 but outside of the basket-shaped member I9 of the frame structure, an intermediate basket-shaped' member 38 of non-ferrous sheet metal is rotatably vtially as shown in Fig. 4.

dial 31 whose front face is suitably engraved for reading 4absolute bearings, as previously described in connection with Fig. 3. A shaft 1I extends through entral reentrant boss 2|! and is supported therefrom by ball bearings as shown. Pinion 40 is fixed to this shaft 1| and disposed so as to engage with the teeth of gear 39. Fixed to the inner end of shaft 1I is a pinion 12 which isadapted to engage with a gear on the Sperry compass repeater'mechanism" 4I (not shown in Fig. 5). Also xed to shaft 1| is another gear 42 which is adapted to be engaged by a crown gear (not shown) in order to permit manual rotation of dial 31.

Through the center of quill 5I yextends the main indicator shaft 29 which is rotatablyjournaled upon an inside bearing surface of this quill. On the rear or inner end of this shaft 29, a spur gear 30 is fixed by means of set-screw 13. End motion of shaft 29 is restrained by setscrew collar 14 which bears on the end of quill 5| and by the hub portion 15 of compensator arm 32, this hub being'also pinned to shaft 29 by a tapar, pin 16. On the front or outer end of shaft 29 is rotatably journaledpointer cap 3| to which pointer 33 is attached by screw 34. End motion of this cap 3| is restrained Aby screw 11 which is threaded into shaft 29 and engages a slot in cap 3| as shown'in the drawings. The slot in cap 3| is sufllciently long so that this cap may be rotated approximately 25 'degrees in either direction from its normal position on shaft 29. The compensator linkages for controlling the displacement of cap 3| on shaft 29 are essen- Bell crank arm 44 rotatably pivoted on a. reduced neck portion of collar 19 carries a roller 46 rotatably held by a shouldered rivet at the end of its longer arm.'

At the end of the shorter arm of this bell crank 44, link 43 is pivotally connected by means of pivotally connected to the flange of cap 3| at such a point that the distance from the center of shaft 29 to the pivot point on the flange of cap 3| is equal in length and parallel to the distance from the bearing of bell crank arm 44 on collar 13 to the pivotal connection between this bell crank arm 44 and link 43: The rotation of cap 3| around shaft 29 is'therefore always exactly equal to the rotation of bell crank arm 44 around its ,bearing collar 13. A spring 19 is positioned around the lower reduced neck portion of collar 19 and one end of this spring is hooked through a hole in arm 32. The free end of spring 19 bears against a flanged pin 9|! fixed in the lower surface of the flange of cap 3|, so that this spring 19 tends to rotate the cap counterclockwise, as viewed from the front of the control and indicating unit. By the action of this spring, therefore, roller 46 is pressed inwardly against the edge of cam plate 35. As explained inconnection withV Fig. 4, this cam 35 is suitably cut so that cap 3| and pointer 33 will be displaced with respect to shaft 29 by the same number of degrees as the true direction of the incoming signal is displaced with respect to the apparent direction to which the loop antenna must be set for minimum reception.

For the purpose of rotating antenna gear 9 in the proper direction with respect to handwheel Gara jack shaft 25 is provided journaled in extension 26 of the casting i8 of the frame struc- 10 ture. This jack shaft is restrained from endwise motion by set-screw collar 8| and by the hub of bevel gear 21 which is pinned to this jack shaft4 by a taper pin. On the front`end of this jack shaft is iixed a helical gear 24 which meshes with' ring gear 59, the latterlalso being helically cut.

On the rear end of "jack shaft 25 is fixed a spur gear 28 which meshes with the spur gear 30 pre-- viously described. Spur gear 28 and helical gear 24 are of the same pitch diameter; also, helical ring gear 59 and' spur gear /30 are of the same pitch diameter, so that shaft 29 is rotated synchronously with handwheel 63. The gear reduction ratio between bevel gear 21 and antenna gear 9 i s equal to the reduction between spur gear 28 25 and spur gear 30,- so that the antenna is rotated.

through the same number 'of degrees as indi-f cator shaft 29, both of these rotations being the same as the rotation oflhandwheel 99.

The drum-shaped casting i8 oi the frame. 30 structure is machined so asI to t accurately into the front panel of the complete direction. finder cabinet, so that the control and indicating unit will align itself accurately with respect to this cabinet. This .insures that bevel gear 21 will mesh properly with antenna gear member 9 when,

the control and indicatingunit is inserted in the panel. 'I'he engagement between the latter two gears, -21 and 9, is the only mechanical engage- .ment in which accuracy is essential, which must '40 be effected when the control andindicating unit is placed in the direction nder binet. The only other mechanical engagement which must be effected between this unit and the remainder o f the direction nnder,v is an engagement between a control knob onthe side Aof the cabinet (not shown) and the shaft which carries the previously mentioned crown gear for engaging gear 92. A11 other gearing, such as the gear train for inter-relating the rotation of shaft 29 and the rofor ot/ating dial 3l from driving mechanism 4|, remains in engagement when the unit is removed from the direction nder. For this purpose the Sperry conipass repeater mechanism Bi is 55 mounted upon legs 83 of casting i9 of the frame.

' structure, so that this driving mechanism 9ire' mains xed to the control and indicating unit when this unit is removed from the tion nder.

It is preferred to use non-'ferrous metals for every portion of the unit except in the "Sperry repeater mechanism.- If this mechanism is f omitted the completeunit will be non-magnetic. In the whole direction finder, moreover,` non-fercs rous metals are employed except in the loud speaker 4 and in those portions of the receiver '3 which require iron.

n will be noted met in every embodiment of my invention. all the rotating parts with the ex ception of pointer cap 3iare mounted directly .Y 4upon the stationary frame structure so that there i are no forces tending to rotate any of these parts except' the desired forces which 'rare intended to control such rotation. Even basket member v99,

for example, although it is located'inside of the radio answer remove screws 58 and thus 50 `tation of the handwheel aswell as the gear train jply forces for straining or bending this delicate mechanism except by actually removing the glass dial and extending force upon the pointer itself. By this arrangement the possibility of straining the compensator mechanism and thereby destroying itsaccuracy is almost eliminated since it is very unlikely that large stresses willbe applied to the pointer and since. in any case, the pointer is sumciently fragile -so that excessive stresses can not be tranmitted through it. It shoul furthermore be noted. that the cam plate 35 is eadlly accessible for changing or recutting, since this cam can be removed without even taking the control and indicating lmit out ofthe radio direction finder cabinet. In order to remove this cam plate 35, itis merely necessary to snap out spring ring 69 and remove theglass dial 81. and'then to take out the screws Iwhich attach dial plate 38 to lug 55. Now by loosening'the single screw 34, pointer 39 may be removed and then the complete assembly |99 which Vincludes the dial plate 36 and the cam 35 maybe taken out of the compass. For minor alterations in the surface of cam it is not even necessary to detach this cam from the dial plate 36; for'more extensive alterations or when it is desired to replace' cam by another cam. it is n rely necessary to l take the cam away from the dial plate. l Y

.While I have described the vparticular embodiments of my invention for the.purposes of illustration, it should l be understood that various modifications and adaptations thereof occurring tooneskilledintheart.maybemadewithinthe spirit of the invention, as set forth in the app endd claims. v y What is claimed is: 1. In a radio Vsignal direction nder ci the type wherein by manually settlngan antenna to a desired relationship with a signal an 'indicator is caused toindicate the bearingsof the signal, a control and indicating mechanism comprising aA stationary frame memberra handwheel rotat- .ably-mounted on said frame member and geared lto' the antenna, 'a pointer' carried by a. shaft which is'driven by said handwheel and is-rotatably vmounted and-encompassed during rotation by said handwheel, and two concentric dials of which one is rotatably moun ted on said frame member outside of said-shaft and inside of said -handwhee l.,.'` Y,

2.' In aradio .direction finder for use on 'e movable ehi, the ander having e directional: antenna and being of the type wherein by j manually setting' the'antenna to a desired relationshipwith a signal an indicator is caused to l s of the signal, a control and indicating mechanism comprising a stationary .frame member.` a handwheel rotatably lmounted onvsaid frame member and geared to the antenna.'a pointer coupled to a shaft which is geared to and` handwheel-dnd is' rotatably.

mounted on said frame member and encoml.passed by said' handwheel, and two concentric dials of which one is rotatably mounted on said frame member outside of said pointer shaft and inside of said handwheel.

3. In a radio signal direction iinder for use on ,a movable ship, the iinder having a directional passed .during rotation by said handwheel, and

two substantially planiform concentric dials mounted on said frame member outside of said pointer shaft and inside of said handwheel, one of said dials beingY graduated for reading bearings with respect to the ship and the other ,dial being rotatably mounted and being graduated for reading absolute bearings.

4. In a radio signal direction finder for use on a movable ship, the iinder having a directional antenna and being of the type wherein by manually settingfthe antenna to a desired relationship with a signal an indicator is caused to indi,- cate the bearings of the signal, a unitary control and indicating mechanism comprising a stationary frame member, a handwheel rotatably mounted on said frame member, a driving gear adapted to be rotated by said handwheel, a pointer carried by a shaft which is driven by said handwheel and is rotatably mounted on said frame member inside of said handwheel, two concentric dials of which one is rotatably mounted on said frame member outside of said pointer shaft and encompassed during rotation by said handwheel, said whole unitary mechanism being readily removable from the remainder of the direction nder, and a driven gear connected to rotate the directional antenna, said gear being adapted to engage the driving gear of the unitary mechanismmhen said mechanism is in place in the direction finder.

5. In a radio signal direction finder the combination of a frame, a handwheel rotatably mounted thereon, a directional antenna geared to said handwheel, a first dial rotatably mounted and' encompassed during rotation by said handwheel, a second dial mounted inside said rst dial, a

pointer in front of said second dial and adaptedto rotate in cooperative relation with the front faces of both of said dials, and a pointer-driving train of mechanism extending from the pointer rearwardly through said second dial to said handwheel whereby said `pointer is rotated by said handwheel through said train.

6. In a radio signal direction nder a unit comprising a frame, a handwheel rotatably mounted thereon, a gear adapted to be rotated by said handwheel, a iirst dial rotatably mounted inside said handwheel, a second dial mounted so as to be encompassed by said first dial, a 'pointer in front of said second dial and adapted to rotate in cooperative relation with the front faces of both of said dials, a pointer-driving train of mechanism extending from the pointer rearwardly through said second dial to said handwheel whereby said pointer is rotated bysaid handwheel through said train, said unit being selfcontained and readily removable from the rest of the direction nnder, a 'second gear adapted to be engaged by the gear of said unit when the unit is in position in the direction finder and a directional antenna coupled to said second gear.

7. In a radio signal direction finder the combination of three concentrically nested basketshaped members of which the outer two are rotatably mounted, a handwheel fixed to the outer member, a directional antenna geared to said outer member, a substantially planiform dial fixed to the intermediate member, a second substantially planiform dial lnxed to the inner member, a pointer disposed in front of said second vdial and adapted to rotate in cooperative relation with the front faces of both of said dials and a train of mechanism extending from said outer member through said intermediate and inner members and through said second dial to said pointer for rotating said pointer in response to the rotation of said handwheel.

8. In a radio signal direction nder the combination of three concentrically nested basketshaped members of which the outer two are rotatably mounted, a handwheel iixed to the outer member, a directional antenna geared to said outer member, a substantially planiform dial fixed to the intermediate member, a second substantially planiform dial xed'to the inner mem.. ber, a pointer disposed in front of said second dial and adapted to rotate in cooperative relation with the front faces'of both of said dials and a train of mechanism extending from said outer member through said intermediate and inner members and through said second dial to said pointer for rotating said pointer in response to the rotation of said handwheel, said train of mechanism including a quadrature compensating device disposed within said inner basket-shaped member.

9. In a radio signal direction finder the combination of three concentrically nested basketshaped members of which the outer two are rotatably mounted, a handwheel fixed to the outer member, a directional antenna geared to said outer member, a substantially planiform dial xed to the intermediate member, a second substantially planiform dial ilxed to the inner member, a pointer disposed in front of said second dial and adapted to rotate in cooperative relation with the front faces of both of said dials, a stub xed to said pointer and extending through said second dial into the interior of said inner basket-shaped member, a shaft extending into the interior of said inner member, a gear train coupling said shaft to the outer member, a cam iixedly mounted within said inner memberand means disposed within said inner member for rotating said stub under the joint control of said shaft and said cam.

10. A radio signal direction iinder comprising a frame structure having a cavity and reentrant boss with an. external cylindrical surface in said cavity, a control member journaled on said cylindrical surface and comprising a handwheel and a ring gear, a directional antenna mechanically coupled to said control member, a central shaft journaled in said reentrant boss, an indicating 1 pointer driven by said shaft, and a train of gears adaptedto drive said shaft responsive to the rotation of said ring gear.

in said cavity as to define a substantially annular cavity, means for rigidly iixing said basket member to said frame piece in such relative position, a control member rotatably journaled Within said annular cavity so formed, a rotatably mounted shaft extending into the interior of said basket member, a gear train for driving said shaft in response to the rotation of said control member, a handwheel fixed to said control member, a pointer disposed for rotation in front of said basketshaped member and during rotation encompassed by said handwheel, a cam fixedly supported from said basket-shaped member and a. quadrature compensating mechanism for driving said pointer from said shaft under the control of said cam.

12. In a radio signal direction nder, a frame piece having a cavity and ahole in the bottom of said cavity, a basket-shaped member having a quill adapted to t in said hole, means including said quill and the surface of said hole for xing said basket member rigidly with respect to said `frame piece so as to constitute a rigid frame structure, a ring gear rotatably mountedutside of said basket-shaped member and inside of said frame piece, a handwheel xed to said ring gear, a rotatably mounted shaft extending into the interior of said basketshaped member, means for driving said shaft from said ring gear, a pointer rotatably mounted so as to be encompassed by said handwheeland a cam cntrolled' compensating mechanism for driving said pointer from said shaft.

STEPHAN R.. WAGNER. 

